|
 |
 |
 |
|
Last updated |
|
|
|
|
|
Last updated |
| Other
Opinions |
|||
| The idea that consumption of a diet rich in fruits
and vegetables and hence natural antioxidants is strongly associated with a reduced
incidence of cancer and heart disease is now accepted by almost all authorities. Many
epidemiological studies and some intervention studies have established that
supplementation with individual antioxidants has a protective effect but several
authorities feel that further long-term, large-scale intervention studies are required to
prove that supplementation works. They generally express the view that the benefits of
fruits and vegetables consumption may prove to be due to factors as yet unidentified or to
the interplay between the vast range of natural antioxidants present in fruits and
vegetables.
Three studies have produced unanticipated results. Alpha Tocopherol & Beta Carotene (ATBC) found no protective benefit from supplementation with low levels of synthetic vitamin E and synthetic beta-carotene and reported negative outcomes among chronic heavy smokers, as did the Caret trial of synthetic beta-carotene with smokers or asbestos workers. Certainly smokers should avoid synthetic beta-carotene, and should instead follow a diet rich in fruits and vegetables. ATBC did, however, show a decrease of 41% in prostate cancer deaths in men taking vitamin E compared to men who did not receive vitamin E. A trial designed to test selenium supplementation against skin cancer found no preventive effect. However, participants receiving selenium had a much lower incidence of cancer, and the death rate from all cancers was halved. Two leading medical institutions, the American Heart Association and the American Cancer Society, have advised that more long-term, large-scale blinded intervention studies are required before they recommend antioxidant supplementation to all. I share their enthusiasm for more research and trust that in the future, my children will benefit from these findings. The Food and Drug Administration has the unenviable task of regulating "health claims" on the labels of neutraceutical products and has rejected label claims including "antioxidants prevent cancer", on the grounds that the required scientific consensus does not yet exist. Recently the appeals court ruled that the FDA should first define what scientific consensus is and then reconsider this claim. But the doctrine that only drugs cure or prevent disease and that dietary supplements help maintain the structure and function of bodily systems, is itself obscure and in conflict with much of what we know of preventive medicine. The fifty million Americans who take dietary supplements do so because they expect that this will help prevent disease. It is important that they have access to scientific knowledge as to the dosages and combinations which are likely to be effective. |
|||
|
|||
 |
 |
||
